I have enabled online archiving for few users which falls under Exchange Online Plan 2. The users can see the archive folder in outlook web app but not in the outlook client. We use office 2010 pro here. Any idea, what needs to be done?

I am going to assume its not on a terminal server, but a users actual machine.

From the researching i have done on this same exact topic just in the last week, i have found out that it can come down to the copy you have installed. The articles i found online said that users that had TechNet or MSDN copies installed, it would not work, but they had to install or use a Legit, Full, License key, not an MSDN or TechNet. Now, i did not find anyone talking about a Volume key, so, if you have another key, or another machine with the Non-Volume key, can you try that one?